mikeDnight

As Vixen HR's are currently unavailable, id suggest grabbing a Takahashi 4mm TOA. Then id get a 17.5mm Morpheus, which will give you a nice wide field with dark sky background and high contrast. The 17.5mm Morpheus barlows beautifully, so you'd have essentially a 9mm eyepiece giving great views. Or, forget the expensive eyepieces and buy a binoviewer and a second 15mm TV plossl or ES 16mm. Then buy the 17.5mm Morpheus. You'll not regret it!

When its cloudy and raining you'll find yourself just sitting and staring at your beautiful refractor, with a slightly increased heart rate.

This kind of sums it all up really. Especially the "love at first sight" comment.

May be its too bright in the 12" Mark? I remember struggling to see much detail on a 5" arc Mars in a 10" F6, but in the 100mm refractor it was more obvious, though not easy.

May be we should forget the deeper reasoning and resort to complete immaturity. (My comfort zone!)

I absolutely love this!!!

The greater depth of focus may also have some truth in it, but here comes another spanner. If depth of focus is the problem, then how can a short focal length apo nearly always deliver an image with better definition? Ive no idea, just thinking out loud. Here's another thought. If a primary mirror needs to be at least 4X more accurate on its surface than anyone of the at least four lens elements of a refractor, if a secondary flat isn't also four times better than the combined lens accuracy, has it compromised the system?? It's enough to make my brain hurt!

That sounds like a reasonable hypothesis Craig. But just to throw another spanner in the works based on my own experience with larger telescopes. At my local astro club there is a very nice 8.5" refractor and many reflectors of various aperture, both large and small. If its due to seeing that a scope is held back, then why does the 8.5" refractor always outperform all the reflectors on the same night, including those of equal aperture, every time, as regards sharpens, contrast and definition? Could it be that reflectors need to be figured to a much higher tolerance ( at least 4 times more accurate on the mirror surfaces) than anyone of the four surfaces of the refractor, and thus by nature are more susceptible (sensitive) to bad seeing?

I'm not sure about that Stu. I can't focus on a thing within a metre of my face without wearing spec's. I put everything down to having a reasonably good planetary site with a reasonably steady atmosphere much of the time. The spec's do make me look more intelligent though!

FLO should hand them out free of charge to moderators!

I usually look for the brightest areas first, which are nearly always the cusps then the limb. Then I observe the terminator to see if there are any bright regions, and then the main surface. It's all very subtle, but things may become a little more obvious with a blue wrattan 80 or 80A filter, or yellow 11 to 14. Orange W21helps with albedo features on Mars so it might also help with the subtle shadings in Venus cloud tops though I can't remember ever trying it, but I suspect I have.

Yes, just a cheap as chips Tak prism diagonal, nothing fancy.

I used a couple of blue 80A filters in my binoviewer a couple of years ago while observing Mercury. It really did seem to draw out subtle detail, but it also seemed to have the effect of steadying the image somehow. I'm not sure why that would be, but if it works I'm happy using it. The same with your minus violet filter. Whatever works is worth using. I've had pleasing results in the past using a neodymium filter and even an OIII and UHC filter on Mars. Not playing by the rules can be liberating sometimes!

Sorry Jeremy! There was a brief moment when I thought I'd glimpsed it, but it was fleeting and it didn't occur again, so I think I'd be deluding myself if I believed I'd seen it. Perhaps if I'd lowered the magnification quite a bit I might have stood a better chance, as the atmosphere at the Sirius level was becoming a bit rough to be honest.

Often overlooked due to its apparent lack of detail, Venus can be a surprisingly interesting visual target. No filters were used in any of the attached sketches and being observed through 100mm refractor using a prism diagonal, the orientation is north top with preceeding to the left.

Excellent images Paul. It was good to get a dry, clear spell for a change.

It seems to have been raining or cloudy nearly every night for months, and when it has been clear I've had to be elsewhere. Life gets in the way! This afternoon however, the Moon was high in a clear blue sky and the Sun, though still above the horizon, had set behind a small wooded hill across from my house. I rushed to set my refractor up on its mount in the observatory, rolled back the roof and aimed the scope at the Moon. Earlier this week I'd bought a nice second hand 8mm Burgess TMB eyepiece and wanted to try it out. The Moon, being set against a blue sky lacked some contrast, yet the 8mm gave a very pleasing view, and I could imagine how good it would be as the sky background darkened. So to pass the time, I aimed the scope at Venus. The 8mm gave me 93X in my 100mm F7.4, so I used a 2X Celestron Ultima Barlow to increase the image scale to something I could work with. Now that Venus was larger in the eyepiece, I made a sketch. Then I was required to go back into the house for tea, so I capped the scope and closed the roof. It's a good job I did, as soon after it began to rain again. I decided to spend a few minutes after tea turning my rough eyepiece sketch of Venus into a finished drawing in my observing book. Then as luck would have it, the rain stopped again and the sky cleared, revealing a beautiful Moon against a dark sky. And on returning to the telescope I was pleased to see the seeing was really quite steady. The Moon was beautiful in the 8mm Burgess TMB now that the contrast was higher. Using the Ultima barlow gave some highly detailed views which confirmed to me just how nice these eyepieces are. Now to make things just a little more interesting, I thought I'd compare the 8mm with my existing 7.5mm Ultima. Its good to remember that the Burgess TMB were designed for use in the superlative TMB triplet Apochromats, while my Ultima eyepieces are around 30 year old and were themselves state of the art in their time. How would these two eyepieces compare when used in a top class apo? Well the 8mm Burgess TMB was a joy to use. It's relatively wide field and long eye relief made it very comfortable to use. There's something glorious about seeing the whole moon in the field of view at over 90X with space around it, while at the same time being able to see highly detailed views of its cratered surface. I liked this eyepiece very much, it is sharp to the very edge, though it does suffer from noticeable field curvature. It also barlows beautifully in the 2X Ultima. The 7.5mm Celestron Ultima by comparison, and which was state of the art in its day, is still state of the art. After studying a complex region along the terminator using the 8mm, I quickly swapped the 8mm for the 7.5mm and the difference was immediately obvious. The difference in magnification was only 6X, so really quite negligible, yet the image quality was definitely in favour of the Ultima, which despite its narrower field and shorter eye relief, revealed finer, sharper detail with increased clarity. I was really quite surprised at just how much sharper the Ultima was. Now, all enthused by the image quality of the Ultima, I rushed back into the house to bring out my little box set of Vixen HR eyepieces. And again I carefully studied the same complex region on the lunar terminator using the 7.5mm Ultima. Then swapping the 7.5mm for the 3.4mm Vixen HR I expected the seeing to begin to have an effect on the view, but it didn't. The 3.4mm HR was jaw droppingly sharp, even sharper than the already wonderfully sharp Ultima despite the power increase from 99X to 218X. The 3.4mm HR was so comfortable to use, having great eye relief and an amazingly bright sharp field. I decided to play for a while looking at a few stars starting with Betelgeuse, which was the most textbook perfect star image imaginable. At this point I swapped the 3.4mm HR for the 1.6mm HR, and still looking at Betelgeuse I imagined this would push even a 100mm Takahashi over the edge. It didn't! The star was perfection, so leaving the 1.6mm in the diagonal, I aimed at Alnitak, which along with its companion was embedded in nebulosity. The scope was now working at 463X and seemed to be indestructible, that is until I aimed it at Sirius, which boiled in the increasingly turbulent atmosphere as I got lower in the sky. So it was back to the Moon for a last look, but this time at 463X. The HR eyepieces are really something else. The views were still surprisingly sharp and gave me an almost 3D feeling to the view. The comfort, brightness and sharp full field effortless views, even in the 1.6mm left me in awe of the eyepiece. But its equally a testement to the telescope and its prism diagonal. The clouds were once again beginning to move in, so I again capped the scope, closed the observatory roof, turned on the electric heater and just contemplated what I'd just witnessed. Sometimes it's good to just play with our gear for no other reason than to have fun, and refamiliarize ourselves with the tools we have at out disposal.

I think the aperture of your 5" SCT is where its magic lies, and may actually be the most suitable scope for your needs. I'm not surprised you prefer it to your 80ED, but the 80ED will give sharper star images. Moving to a 120ED you'll find a significant jump in performance both compared to the 80ED and your 5" SCT. The ED is a much more capable, all round performer. It's lunar and planetary views will be better defined and its deep sky views will be brighter. It's star images will be sharper and it will give you both low power rich field views and sharp high power views. Even so, your 5" SCT is a highly manageable instrument, and there is a lot of advantage in using a telescope that is easy to use. The 120ED will give better all round performance, but it is bigger. (Looks great though!) If you were actually being serious about going down the Takahashi route, I would personally suggest choosing from one of their refractor lines. Their FC100D series are light weight yet extremely capable, and any one of the line would give you better performance than your 5" SCT. If you really needed greater aperture, then the 120TSA is worthy of serious consideration. Larger than that and Tak refractors become heavy and very expensive. They do make some of the world's best telescopes though, so if you're looking for that lifetime keeper, then you've chosen a top tier manufacturer. The Mewlons offer greater aperture at reasonable prices (Takahashi prices), but inch for inch a refractor has the edge in sharpness.

Hi Baz, At the time of the 463X observation I was testing a new Vixen 1.6mm High Resolution eyepiece. The view through my scope at the time was surprisingly good, but generally I don't use such powers for Venus. Venus is large as a target and 180X to 230X should be more than enough to produce a meaningful image scale. The two sketches were made only a few minutes apart, yet I feel there is enough difference in detail between the two powers to make experimentation worthwhile. At the same time the two sketches are so alike that it gives me confidence in the accuracy of both observations.

Detail on Venus is very subtle Baz and can be overpowered by the planet's brilliance. One way to help to draw it out is by not directly looking for it. Instead, look for the most brilliant regions. Perhaps making a basic outline sketch will help. The cusps (polar regions) are generally the brightest and can appear as silver polar caps, (one is often seen as being a little larger than the other). You might indicate these on your drawing as a dashed line. The limb of the planet is also brilliant silver and quite thin; however study it carefully for undulations, where the brilliance increases. Next look along the terminator, which isn't as sharp as the limb. Often you might detect brighter regions, sometimes small, sometimes larger, just dipping into the terminator shadow. Looking lastly at the main surface, you may be able to see wraithlike whips of brighter areas. You can number the bright regions in order of brilliance from 1 to 5 if it helps. At this stage you'll have produced an outline of the bright areas, or if you prefer, an outline of the darker cloud tops. Next, just study the less bright clouds for any area that may be darker than the rest. Often there may be a darkening around the south cusp and sometimes another mid way along the terminator. The North cusp too may have a dark region extending from the terminator. To reduce glare, try using high powers if seeing allows. It's often better to observe Venus against a twilight sky rather than a black sky. Wrattan 11 to 14 colour filters can help as can wrattan 80A it wrattan 21. The attached sketch shows high power sketches of the planet. It's good to remember though, that the shading on the sketch is significantly darker than the visual appearance of the planet through the telescope.

I'm struggling to understand why the image in your scope is tiny? Unless you're using a low power eyepiece Venus should easily show itself as a relatively large object. It might seem like a silly question, but are you sure you are looking at Venus and not a near by star? Is your finder scope accurately aligned? Attached is a sketch of Venus made using my 4" refractor at 118X, so you should be seeing a definite phase to the planet. The cloud detail is much more subtle visually, so don't worry if you don't see that at first.

Hi Rob, When low in the sky, the telescope has to look through a greater depth of atmosphere, and unless the atmosphere is steady its going to struggle to focus the image. You may also have local heat sources or sources of turbulence such as motorways and town centres to consider. To be honest, I think your video is very good and it shows your scope is good too. Try observing when the moon is above 30° high, as below this any telescope is going to have a battle against the atmosphere unless its unusually steady. The best nights are yet to come for lunar observing as the spring moon will be high in the sky right through until May.

I suspect things will settle down after the initial turbulence, and Vixen will be on the menue again.

Everything is dependent on what mating elements are involved, and the lens design.

I'll PM you. ☺